Decouple capture timestamp and reference time

content/browser/renderer_host/media/video_capture_host.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/media/video_capture_host.h"
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 74 matching lines @@
   if (entries_.find(controller_id) == entries_.end())
     return;
 
   Send(new VideoCaptureMsg_FreeBuffer(controller_id, buffer_id));
 }
 
 void VideoCaptureHost::OnBufferReady(
     VideoCaptureControllerID controller_id,
     int buffer_id,
     const scoped_refptr<media::VideoFrame>& video_frame,
-    const base::TimeTicks& timestamp) {
+    base::TimeTicks reference_time) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   if (entries_.find(controller_id) == entries_.end())
     return;
 
   VideoCaptureMsg_BufferReady_Params params;
   params.device_id = controller_id;
   params.buffer_id = buffer_id;
-  params.timestamp = timestamp;
+  params.timestamp = video_frame->timestamp();
+  params.reference_time = reference_time;

[miu, 2016/06/07 20:03:47]

There's no need to add a new |reference_time| to the IPC message.
VideoFrameMetadata already has what you need:

  video_frame->metadata()->SetTimeTicks(VideoFrameMetadata::REFERENCE_TIME,
reference_time);

Also, this will allow you to eliminate the extra |reference_time| argument to
this method (and in several other places). Just set the metadata property
upstream of here, and let the VideoFrame carry the REFERENCE_TIME in its
metadata as it is passed throughout the stack to the render process.

[qiangchen, 2016/06/08 18:04:30]

Done.

   video_frame->metadata()->MergeInternalValuesInto(&params.metadata);
   params.pixel_format = video_frame->format();
   params.storage_type = video_frame->storage_type();
   params.coded_size = video_frame->coded_size();
   params.visible_rect = video_frame->visible_rect();
 
   Send(new VideoCaptureMsg_BufferReady(params));
 }
 
 void VideoCaptureHost::OnEnded(VideoCaptureControllerID controller_id) {
@@ skipping 228 matching lines @@
     return;
 
   if (it->second) {
     media_stream_manager_->video_capture_manager()->StopCaptureForClient(
         it->second.get(), controller_id, this, on_error);
   }
   entries_.erase(it);
 }
 
 }  // namespace content